Process c j



C. PEARSON.

I PROCESS OF FORMING KNlFE HEADS FOR MOWING MACHINES.

APPucmou mu) NOV.8. 19m

1,319,485. Patented Oct. 21,1919.

InvenZSr Ckavlaa Peamo n,

UNITED STATES PATENT OFFICE.

CHARLES PEARSON, OF CHICAGO, ILLINOIS, ASSIGNOB, BY MIESNE ASSIGNMENTS, TO INTERNATIONAL HARVESTEB COMPANY, A CORPORATION OF NEW JERSEY.

PROCESS OF FORMING KNIFE-HEADS FOR MOWINGMACHINES.

Application filed November 8, 1917.

To all whom it may concern.-

Be it known that 1, CHARLES PEARSON, a citizen of the United States, residing at Chica 0, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Processes of Forming Knife Heads for Mowin Machines, of which the following is a fu 1, clear, and exact specification.

This invention relates to knife heads for mowing machines, and more particularly to knife heads formed of steel by forging.

Up to the present time the majority of mower knife heads have been cast and then annealed and hardened to properly condition them for the service required. Knife heads so formed have given much trouble in times past by breaking under the severe strains to which they were subjected by the constant reciprocation of the knife of the mower. In view of these difliculties it is now proposed to form a flanged knife head from steel by forging the same and using suitable dies to obtain the desired shape and form.

The object of the present invention is to overcome the difliculties experienced with cast iron annealed knife heads by producing a knife head of similar outline but formed of forged steel.

In the drawings I have illustrated the various steps employed in the process of producing such a flanged steel knife head, and in these drawings- Figure 1. is a top plan view illustrating the knife head after it is first forged and in its first stage;

Fig. 2 is a side elevation of Fig. 1; r

Fig. 3 is an end elevation of the same;

Fig. 4 shows a plan view of the knife head in its second sta e of development;

Fig. 5 is a si e elevation of the construction shown in Fig. 4;

Fig. 6 is an end elevation of the same;

Fig. 7 shows a plan view of the finished knife head;

Fig. 8 is a side elevation of the construction shown in Fig. 7 and Fig. 9 shows an end elevation of the same.

The construction shown in Fig. l is produced by placing a suitable mass of steel beneath a forging hammer, which is provided with a suitable die, and compressin this mass of steel. By this, the first step 0 the process, I form the usual elongated Specification of Letters Patent.

Patented Oct. 21 191.9.

Serial No. 200.897.

shank portion 10, the vertical rib portion 11, and the laterally extending flanges 12 of the knife head. There is also formed an upwardly extending projection 13, which is cylindrical in cross section and is rounded on its upper surface, as shown at 14. This upwardly extending cylindrical projection adjoins the vertical web 11. After the head shown in Figs. 1, 2 and 3 has been formed, it is turned at right angles, or if retained in the horizontal plane the impressing dies are forced inwardly at right angles to the direction of force of the original compression hammer.

The dies employed in the second step of the process are suitably formed to produce the spherical portion 15 of the head illustrated in Figs. 4, 5 and 6. These spherical dies also draw out the metal from the flanged base of the knife head, as clearly illustrated in Figs. 5 and (3, leaving a vertical Web portion 16 betwec'n the spherical head 15 and the baseof the knife head. the second step of the process there is also forced out a rim or flange of metal 17, and to complete the process this flange is cutoff by means of suitable dies, or is filed off, leaving the finished product illustrated in Figs. 7, 8 and 9. It will be understood that any edges or flanges formed by the excess metal squeezed out by the dies in other steps of this process or method, can be cut off in a similar manner, the elimination of this ex- Cess metal being a mere mechanical detail and not constituting an essential step in the process. In these views I have illustrated the knife head as it is used on a mower and provided with the shank 10, the vertical web 11, the outwardly projecting lateral flanges 12, and the spherical bearing member 15, which is received by the pitman straps and transmits motion from the pitman to the knife head and cutter bar.

From the above description it will be seen that l have invented a simple and practical process of forming a one-piece knife head out of steel and provided with laterally projccting flanges on all sides of the spherical shaped bearing member, which flanges are essential to the successful operation of a knife head of this character, both for strength and for ,the reason that the flanges form the bearing surface for the knife head as the same is reciprocated by the itman.

While I have in the above escription By v outlined one embodiment of my invention, it will he understood that the same may be modified without departing from the spirit of the invention as expressed by the following claims.

hat I claim as new is:

1. The process of forming a steel knife head, which consists in forging a head with outwardly projecting flanges and an it wardly projerting web and an upward y projecting cylindrical i'nemher, and compressing said cylindrical men'iher by suitable dies acting in a direction at right angles to the plane of said web [6 form a spherical hearing member.

2. The process of forming a steel knife head, WlllCll consists in forging a flanged head with an upwardly extending pro1eetion, turning said head at right angles and compressing and drawing said projection between suitable dies to form a spherical bearing n'ieinber.

3. The process of forming a one piece steel knife head, which consists in forging a fiat 'bearing surface, an outwardly projecting elongated shank, and an npwardl projecting web intermediate the side edges of said bearing surface, and in r.-on'ipressing said web in a direction transverse to the plane thereof.

In testimony whereof I affix my signature.

CHARLES PEARSON. 

